[Zope] Problem with running same script at a time

Hello list, I use zope2 latest cvs version I have experienced that when i run a python srcipt (it is a long postresql query) from a user folder then i cannot access this folder from management form while the process is running. If i try at the same time to run this script again the process will start after the other one ends. Other folder are accessible. What do i wrong? Best regards Antal